1. Field of the Invention
The present invention relates to portable computers and more particularly but not exclusively to hand-held computers of the kind sometimes referred to as personal digital assistants.
2. Related Art
A personal digital assistant includes data files defining such items as an electronic diary, address book and other applications such as word processing software, calculators and the like. As more powerful memories and processors have been developed in smaller packages it has become possible to provide quite powerful computers in relatively small portable cases. However, the limitation of miniaturisation occurs when a viewing screen and keyboard are needed for data input and read out. Thus, so called palm top personal computers (PPC) are usually of the order of 15 cm by 7 cm in order to provide a readable screen and a usable keyboard. Such palm top computers are known, for example Psion Corporation have produced a Psion Series 5 (trade mark) PPC having an 8 megabyte RAM and processor while Hewlett Packard similarly produce PPCs as e.g. the HP320LX (trade mark). The capabilities of such PPCs may be enhanced by incorporating so called flash cards enabling the expansion of the RAM by up to 10 megabytes or more while PCMCIA cards may be provided to enable connection of the PPC to telephone networks by way of cellular phones or telephony sockets for communication with other computers and the so called Internet and Intranets.
Most PPCs incorporate a docking arrangement to enable them to be connected with a desktop computer or other main frame for the purposes of synchronisation of data files and the like.
However, generally speaking PPCs are not robust and are prone to damage mainly because of the clam shell design requiring a hinge that opens to reveal the incorporated keyboard and screen. Thus PPCs are more usually used on a desk top or table or may be held in one hand while typing with the other.